Tobacco shipped from overseas to the United States is generally received in foreign burlap wrapped bales weighing about 20-60 kg. Each bale contains tobacco of a selected designation, that is, each individual bale contains tobacco of a specified type, grade, chemical composition, or other criteria. For the purposes of this application, bales of tobacco will be referred to as containing a specified "grade" of tobacco; however, it is to be understood that the term "grade" refers to any criteria applied in sorting the tobacco when packed in the bales.
Once received, the tobacco is stored in its original bale so as to retain its grade identity. It is necessary that the tobacco retain its grade identity during storage so that, in a later stage of processing, it can be selectively blended with other grades of tobacco in desired proportions.
Baled tobacco, which has been shipped from overseas by surface transportation, is received in the United States with a moisture content normally of 14-25% (wet basis). As the tobacco tends to seek equilibrium, it gives up moisture to the surrounding atmosphere. If the bales are not adequately ventilated, this moisture can condense on the surface of the tobacco, and microorganisms present in the tobacco will begin to grow, producing mold.
While the tobacco is in storage, it is necessary that inspections be made at regular intervals. Inspections are necessary to ascertain the condition of the tobacco with respect to mold and also with respect to tobacco beetle infestation. Periodically, it may be necessary to fumigate the areas of baled tobacco storage for control of beetles. It is therefore necessary that, while the bales are kept in the warehouse, they not be so densely stored as to prevent fumigation.
To provide the necessary ventilation, inspection, and infiltration spaces for fumigation, it is presently the practice in the industry to store palletized bales of tobacco on open storage racks in the warehouse. Alternatively, bales of tobacco are stored, in large stacks or bulks, on pallets or dunnage to provide air space under the bulk. These known storage methods are labor intensive both for transporting and storing the bales initially and for removing the bales for subsequent processing. Also, as the individual bales become soft due to humidity changes during the storage cycle, the bales may fall from their position on the pallets.